Office of Compensation Analysis and Support 

Program Evaluation Report

Document Number: OCAS-PER-018 

Effective Date: 7/31/2007 

Revision No. 0

Los Alamos National Laboratory TBD Revision Page 1 of 2 

Author: Signature on file Date: 7/31/2007 Dave Allen, HP Team Leader 

Approval: Signature on file Date: 7/31/2007 J.W. Neton, Associate Director for Science 

Supersedes: None 

RECORD OF ISSUE/REVISIONS 

ISSUE 

AUTHORIZATION 

DATE 

7/31/2007

EFFECTIVE 

DATE 

7/31/2007 

REV. NO. 

0 

DESCRIPTION 

New document to determine which 

previously completed claims require 

evaluation for the effect of revising the 

LANL TBD. 

1.0 Description

The Los Alamos National Laboratory Occupational External Dose Technical Basis 

Document (ORAUT-TKBS-0010-6) was revised on 5/30/2007. This revision (revision 1) 

superseded revision 0 which was issued on 5/10/2005. The purpose of this Program 

Evaluation Report is to evaluate the effect of the change to ORAUT-TKBS-0010-6 on 

previously completed Dose Reconstructions. 

2.0 Issue Evaluation

The primary modification to Revision 0 of ORAUT-TKBS-0010-6 is a change in the 

neutron dose estimate for individuals who were potentially exposed to neutron but were 

not monitored. Both this revision and the earlier version apply a neutron-to-photon ratio 

to the worker’s monitored photon dose to determine potential neutron dose. Both 

revisions provide a median and an upper bound ratio and allow the upper bound ratio to 

be used as a maximizing assumption. However, the revision to the ratios caused the 

median values to increase and all but one of the upper bound values decreased. This 

revision also added a category of work locations. The estimates of dose for unmonitored 

workers may increase or decrease. Because this change only applies to worker’s who 

were not monitored for exposure to neutrons, it will not affect dose estimates for 

individuals with personal neutron monitoring data. 

 

Another modification made in revision 1 is the change in the energy distribution for 

photon radiation at the Los Alamos Meson Physics Facility at the Los Alamos Neutron 

Science Center (LAMPF/LANSCE) in technical area 53. This change affected the 

assignment of non-penetrating dose to electron or photons less than 30 kev. It also 

affected the assignment of penetrating dose to medium energy photons (30 kev to 250 
Office of Compensation Analysis and Support

Document Number: OCAS-PER-018 Program Evaluation Plan 

Effective Date: 7/31/2007 Revision No. 0 Page 2 of 2 

kev) or high energy photons (greater than 250 kev). That change would affect not only 

the dose assigned but the effect of that dose on the probability of causation results for 

those claims which had a dose reconstruction performed using ORAUT-TKBS-0010-6, 

Revision 0. 

3.0 Plan for Resolution or Corrective Action

It is not possible to precisely determine the effect of the change to LAMPF dose 

estimates on Probability of Causation without a new Dose Estimate. However, it is 

possible to determine if the LAMPF energy distribution was used in the original dose 

estimate. It is also possible to determine if an individual was assigned unmonitored 

neutron dose based on neutron to photon ratios and whether the ratio used will increase or 

decrease under the new revision to the TBD. 

In order to determine the effect of these factors, the individual cases must be reexamined. Since the unmonitored neutron dose has the potential of affecting every claim, 

all claims completed prior to May 30, 2007 from Los Alamos National Laboratory with a 

Probability of Causation less than 50% will require a review. NIOSH will request claims 

be returned in which the LAMPF energy distributions were originally assigned using 

Revision 0 for a new dose estimate. NIOSH will also request the return of claims in 

which the original dose estimate utilized a neutron to photon ratio that has now increased. 

For all other claims, NIOSH will review the claim against any other revisions to other 

technical documents that may affect the claim. DOL will be provided with a statement 

for each claim indicating what changes the claim was reviewed against and why the 

change did not affect the particular dose estimate or the Probability of Causation 

calculation. For any claims where it is not possible to provide this statement without a 

new Dose Estimate, NIOSH will request that DOL return the claim for a new Dose 

Estimate. 

 

NIOSH has determined that 300 claims meet the criteria for further review. The 

remaining cases with a probability of causation less than 50% (1 claim) were completed 

using revision 1 of the TBD. NIOSH will provide DOL with the list of 300 claims as 

well as a determination on each claim as to whether a new Dose Estimate is required.